BACKGROUND: Severe TBI is associated with a high rate of mortality and long-term morbidity. Comatose patients with TBI routinely undergo endo-tracheal intubation to protect the airway, prevent hypoxia, and control ventilation. In many places, paramedics perform intubation prior to hospital arrival. However, it is unknown whether this approach improves outcomes.

METHODS: In a prospective, randomized, controlled trial, we assigned adults with severe TBI in an urban setting to either prehospital rapid sequence intubation by paramedics or transport to a hospital emergency department for intubation by physicians. The primary outcome measure was the median extended Glasgow Outcome Scale (GOSe) score at 6 months. Secondary end-points were favorable versus unfavorable outcome at 6 months, length of intensive care and hospital stay, and survival to hospital discharge.

RESULTS: A total of 312 patients with severe TBI were randomly assigned to paramedic rapid sequence intubation or hospital intubation. The success rate for paramedic intubation was 97%. At 6 months, the median GOSe score was 5 (interquartile range, 1-6) in patients intubated by paramedics compared with 3 (interquartile range, 1-6) in the patients intubated at hospital (P = 0.28).The proportion of patients with favorable outcome (GOSe, 5-8) was 80 of 157 patients (51%) in the paramedic intubation group compared with 56 of 142 patients (39%) in the hospital intubation group (risk ratio, 1.28; 95% confidence interval, 1.00-1.64; P = 0.046). There were no differences in intensive care or hospital length of stay, or in survival to hospital discharge.

CONCLUSIONS: In adults with severe TBI, prehospital rapid sequence intubation by paramedics increases the rate of favorable neurologic outcome at 6 months compared with intubation in the hospital.

Notes & Commentary:

This well designed, conducted and reported randomised controlled trial (RCT) of prehospital rapid sequence induction (RSI) of anaesthesia & intubation in traumatic brain injury is the first RCT of prehospital RSI of any reasonable quality in trauma. (See the 2009 Cochrane Review "Emergency intubation for acutely ill and injured patients"). Furthermore the researchers moved beyond mortality as the primary outcome to a more comprehensive assessment of outcome (dependency). They found no difference in hospital outcomes but a strong signal for "good neurological outcome" (normal to moderate disability) in the Prehospital RSI group.

Overall the study was well conducted. Subjects were block randomised by paramedic crew via sealed opaque envelopes. The study was conducted over nearly four years. There were a lot of exclusions - 1045 patients were screened but only 312 enrolled. Most exclusions were either because the patient was being transported by air, was less than 10 minutes from hospital or RSI skills were not available at scene.

As with all such studies there are many questions to answer. Despite the observed outcome differences, there was little difference in the 2 groups on hospital arrival, and in particular there was no difference in their PaO2, O2 saturations or PaCO2 measurements. What then was the benefit of prehospital RSI - does it avoid fluctuations in these variables or is it reducing spikes in intracranial pressure? The preshopital RSI patients statistically spent 12 minutes longer on scene, received approximately 500mls more crystalloid prehospitally, and were colder (by 0.6 degrees C). Is the observed effect due to the protective effects of this mild relative hypothermia (mean 35.0 degrees C).

Additionally there was overall benefit but it was not clear which subgroup had the most benefit from prehospital RSI. There was a trend to suggest that those age <60 received the most benefit. However the trial was really too small for these subgroup analyses and none of the reported subgroups showed worse outcomes with the study intervention. This study joins the list of recent studies showing that good quality clinical trials can be conducted in trauma care, even in the prehospital environment. There is really no longer any excuse for poor design, conduct or reporting of trauma trials. While a further large trial is warranted, this is strong support for prehospital RSI.